Antibody-producing yeast vanquishes deadly gut infection in mice

When people take antibiotics for one infection, another can swoop in to take its place: the bacterium Clostridioides difficile, which causes severe, recurring colon infections that kill nearly 30,000 people annually in the United States, most over the age of 65.

Now, researchers have a new idea for battling C. diff: They have modified yeast to produce and deliver antibodies that defang the bacterium’s two toxins and spur recovery in infected mice.

If it works in people, the genetically engineered yeast, derived from a strain used in a popular probiotic, could be taken as a daily pill to ward off or treat C. diff infections. Study leader Hanping Feng, a microbiologist at the University of Maryland School of Dentistry, calls the proposed method “inexpensive, very easy to manufacture, and a convenient route” for delivery. “The real advance is that they have a living delivery system” for the therapeutic antibodies, says physician and microbiologist Vincent Young of the University of Michigan, Ann Arbor.

C. diff infections occur most often in elderly people who receive antibiotics for an unrelated illness. The drugs wipe out much of a person’s protective gut microbiota, which makes them vulnerable to infection from C. diff spores lingering in a nursing home or hospital. Although most people given antibiotics targeting s recover, the bacterium returns in one in six cases. Sometimes it comes back repeatedly, with deadly results.